If you’ve tried to download a free app but were stopped by a popup like this one, you may be wondering why Apple is trying to charge you for an app that’s supposed to be free. So what’s going on here?

Well, it’ll likely that Apple is trying to collect on previous purchases that were made, but never actually paid for.

You see, Apple does not always bill immediately for in-app purchases or subscriptions. Instead, the charge typically goes through a day or two later. So instead of forcing all their customers to wait until the transaction is complete, they allow users to access the paid app or subscription immediately.